1. Field of the Invention
An improved all composite bicycle frame and fork has three integral mating portions for the main triangle, asymmetric bottom bracket, improved composite layup, wall thickness, and tube geometry providing lighter weight and increased strength in an economical manner. An improved telescoping seat attachment fits an integral seat mast.
2. Description of Related Art
Basic principles of optimum compaction low void composite molding the bicycle industry are described in Nelson, et al, U.S. Pat. Nos. 5,624,519 and 6,270,104, sharing a common assignee with this application. The disclosures in U.S. Pat. Nos. 5,624,519 and 6,270,104 are incorporated by reference as if fully set forth herein.
Fiber reinforced plastic frame manufacture has evolved several alternative approaches. The above approach uses circular section tubes bonded directly to specially formed high strength lugs. This has an advantage of permitting concentration on the hard to mold, high strength pieces, and the use of standard dimension, machine made tubes, for a high performance, yet economical product. Other approaches were to make a single piece “monocoque” as in Trimble, U.S. Pat. No. 4,889,355, which urged that joints in a composite structure were points of weakness, or to butt join and cover tubes, as in Calfee U.S. Pat. No. 5,116,071 or Colnago, Publication EP 0618395. The disclosures therein are incorporated by reference as if fully set forth herein.
The frame avoids the drawbacks of the prior art using principles of optimum compaction low void composite construction specially adapted to the unique shape and structural requirements of high performance frames using a combination of laminates incorporating fibers at different angles relative to one another, while using the molding techniques to form optimal geometry adapted to maximize strength at minimum weight, improve ride quality and permit advantageous attachment of bicycle componentry. The fork additionally provides impact evidence to the user in the event selected stress levels are exceeded.